The Giants were zipping along against National League teams, especially weak sisters like the Chicago Cubs and San Diego Padres, who are dueling for the dubious distinction of the worst team in the league which, because the National League is the weaker of the two leagues, means the worst in baseball.

When interleague play began, the Giants caught the A’s with their best hitters sidelined and won two of three. Then, they hit the good teams in the American League, Texas and the Anaheim Angels, and lost 2-of-3 to them.

Amazingly, they even lost two of three to the sadsack Seattle Mariners.

They’ve also lost their last two series to NL clubs with winning records, the Dodgers and Cincinnati Reds. As they start the weekend series against the A’s in Oakland, it’s been nearly two months since they’ve won a series against a team with a winning record, the Mets in late April.

Does this sound like a team headed for the postseason?

Pitching was supposed to be what would propel the Giants into the playoffs, but that hasn’t worked out as expected, either.

Tim Lincecum, supposedly the staff leader, has had a disastrous season. For a time, Barry Zito was taking up the slack, with a great April followed by a so-so May. Now, Zito has fallen back to his Giants norm, which is horrid. He last looked good against the pathetic Cubs at AT&T Park, but the Rangers treated him like a batting practice pitcher, and the Angels hit him even harder, nine earned runs in 3¹⁄³ innings.

Those are the type of teams the Giants will face in he postseason, in the unlikely event that they get there, so it’s a safe bet that Zito would again be left off the postseason roster, as he was in 2010.

This guy has been stealing money ever since he signed that ridiculous contract with the Giants after the 2006 season, but I don’t blame him. I blame the Giants for a decision which still boggles the mind.

This is not hindsight. I wrote at the time that it was a terrible decision by the Giants, and I was not alone in that opinion. I would say that virtually everybody who had been watching the A’s from the Coliseum press box felt the same way. It’s puzzling that the Giants baseball people couldn’t see what we did, that Zito had been trending down since his Cy Young year of 2002.

And, don’t give me that nonsense about then managing general partner Peter Magowan dictating that choice. Giants general manager Brian Sabean has always made the baseball calls — and he’s made big mistakes since Magowan left, most notably that five-year, $60 million contract for an average outfielder, Aaron Rowand. The Giants had to eat the last year and two months of that contract, and they may have to do that with the last year of Zito’s contract next year.

The only saving grace for the Giants is that they’ll soon be back playing in the NL West, whose bottom three teams were a collective 40 games below .500 after Wednesday night’s games. That can’t happen soon enough.

Glenn Dickey has been covering Bay Area sports since 1963 and also writes on www.GlennDickey.com. Email him at glenndickey36@gmail.com.